While companies are responsible for purchasing and deploying the visual (lights, buoys and daymarkers) and audible (fog horns) aids to navigation (AtoNs), their proposed safeguards must first gain U.S. Coast Guard approval through a Private Aids to Navigation Application (CG #4143) or a buoy-specific application (CG#2554). These regulations  ensure every navigational aid in use meets appropriate safety standards for the open water.

The Code of Federal Regulations (CFR) Title 33 for AtoNs applies to all structures, “temporary or permanent, for which a Corps of Engineers permit is issued.” This applies to a variety of structures, from submerged objects and barges to platforms, landings, caissons, protective barriers, and artificial islands. “The three main considerations for determining AtoN requirements include line of demarcation, structure size and water depth,” says Jason Lacoste, Essi Corporation’s Navigational Aids Manager.

Line of Demarcation

Line of demarcation is generally determined by the amount of mariner traffic in an area. The USCG defines the line of demarcation as “the dividing line used administratively to distinguish between the areas in which structures shall conform to Class ‘A’ and Class ‘B’ or ‘C’ requirements” with AtoN requirements based on this classification.

Structure Size

The USCG requirements vary with structure size. For example, while structures less than 30 feet require only one marine lantern, structures 30 to 50 feet require two lanterns (one each in diagonal corners), and those over 50 feet on any side will need one lantern on each corner.

Water Depth

The USCG categorizes its guidelines by water depth clearances and proximity to fairways and channels:

• Less than 85 feet of clearance requires a red or green lighted buoy with a quick-flash and a half-mile fog signal.
• Clearance of 85 to 200 feet of water requires a red or green lighted buoy with quick-flash if the submerged area is within 500 yards of a fairway or channel. If the area is outside the 500-yard range of the fairway, white buoys with orange bands and flashing white lights are needed.
• Clearance of over 200 feet of water may or may not be subject to AtoN requirements, depending on conditions and circumstances.

Additional specifications for daymarkers, radar reflectors, sound signals, lights, retroreflective materials, identification and plot plans may also be required.

AtoN Effectiveness

While in most cases following these guidelines are sufficient, special circumstances may require adjustments to be made to maximize the effectiveness of an AtoN. Background lighting is one of the most common issues. Offshore, ambient light may be so bright that flashing lights disappear against the horizon. At night, approaching port, AtoNs may dissolve against a city backdrop. Atmospheric pollution, shadowing, obstructions to line of sight and restricted visibility are all degrading factors that can require supplemental measures, such as:

• Altering the colors, rhythmic characteristics or intensity of the light sources
• Modifying the size, shape or color of the AtoN
• Adding or relocating AtoNs
• Sequencing or synchronizing AtoN lights

Sometimes, even upgrading AtoNs alone is not sufficient, especially in developed areas near shorelines. In those cases, cooperative efforts with local authorities may be key in ensuring that AtoNs are easily distinguishable from local lighting.

Offshore Safety and Essi Corporation

Ultimately, the goal is offshore safety – ensuring that each AtoN is not only appropriate to a project’s mission but also as effective as it can possibly be. Essi Corporation has over 25 years of experience working with the USCG to provide companies the most effective marine lanterns, buoys and fog signals for offshore projects. Whether you’re struggling to develop an appropriate AtoN plan or ready to implement an approved design, we’re ready to help. Contact us through our website, or call (337) 837-3774 for more information.